The present invention relates to an indexable cutting insert for an end mill for the machining of contours in a workpiece, which is based on EP-B1-504 608.
An end mill is used during complicated, and severe conditions with intensely fluctuating cutting forces under heavy demands regarding the machining precision. If indexable cutting inserts are used for an end mill, it is important to place such indexable cutting inserts precisely in relation to the tool body and to clamp the cutting insert rigidly on the tool body.
A conventional indexable cutting insert for an end mill, see, for instance, U.S. Pat. No. 6,149,355 and U.S. Pat. No. 5,951,121, has two cutting edges, each comprising a curved edge and a substantially straight edge connecting to one end thereof. In its entirety, the cutting insert has an oval shape as seen in top view. Thus, if the cutting insert is a positive cutting insert, i.e. a cutting insert having a leaning side, it is very difficult to precisely position the cutting insert on a tool body and clamp the same rigidly.
It is desirable to provide a durable cutting insert for a tool body.
It is desirable to provide an easy-cutting cutting insert.
It is desirable to provide a cutting insert that makes precise positioning of the cutting insert in the tool body possible.
It is desirable to provide a cutting insert that may be clamped rigidly in the tool body.
According to an aspect of the present invention, an indexable cutting insert for a milling tool is provided. The cutting insert is asymmetrical in respect of a line through a hole in the cutting insert, the cutting insert comprising two cutting edge portions, each cutting edge portion comprising a substantially straight cutting edge and a curved cutting edge along respective intersecting lines between a clearance surface and a rake face, the curved cutting edges having different lengths, the cutting insert having a bottom side and a first and a second opposite corner, wherein the second corner is defined in plane view by a radius that is greater than, preferably at least twice as great as, a radius of the first corner.